In the injection stretch blow molding process, the plastic is first molded into a “preform” using the injection molding process. These preforms are produced with the necks of the containers, including threads (the “finish”) on one end. These preforms are packaged, and fed later (after cooling) into a reheat stretch blow molding machine, wherein the preforms are heated above their glass transition temperature, then blown using high pressure air into bottles using metal blow molds. The blowing device includes a blowpipe which injects pressurized air inside the preform to expand it and to fit the mold. The blowpipe also participates to the stretching by leaning and pressing on the bottom of preform during stretching and blowing.
PolyEthylenTerephthalate (PET) is a polymer generally used for making bottles, by this injection stretch blow molding process. There is a demand for polymers based on renewables, for example that can be efficiently biosourced, to replace PET.
PolyEthylene Furanoate (PEF) is a polymer that can be at least partially biosourced. Document WO 2010/077133 describes, for example, appropriate processes for making a PEF polymer having a 2,5-furandicarboxylate moiety within the polymer backbone. This polymer is prepared by esterification of the 2,5-furandicarboxylate moiety [2,5-Furandicarboxylic acid (FDCA) or dimethyl-2,5-furandicarboxylate (DMF)] and condensation of the ester with a diol or polyol (ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,4-cyclohexanedimethanol, 1,6-hexanediol, 2,2-dimethyl-1,3-propanediol, poly(ethylene glycol), poly(tetrahydrofuran), glycerol, pentaerythritol). Some of these acid and alcohol moieties can be obtained from renewable crop derived raw material.
It has been disclosed that some containers (bottles) made of PEF have been made. Said containers (bottles) are however believed to be quite basic. There is a need for advanced PEF containers (bottles) notably in terms of compromise lightness (raw material saving) and mechanical properties (assessed e.g. by a drop test), with respect to the widespread PET containers (bottles).
Moreover, the PEF containers obtained by injection stretch blow molding shall have to comply with at least one of the following specifications: processability (windows of process parameters, i.a. temperature), high transparency, food safety, water & airtightness . . . .
The invention aims at addressing at least one of the above problems and/or needs.